Chapter 10: Problem 116
\(f(x)=\sqrt[3]{x}+1\)
Short Answer
Expert verified
Domain: \( (-\infty, \infty) \), Range: \( (-\infty, \infty) \). The function is always increasing with no critical points.
Step by step solution
01
- Identify the function
The function given is \( f(x) = \sqrt[3]{x} + 1 \). It is a cubic root function shifted vertically upward by 1 unit.
02
- Domain of the function
Since the cubic root function is defined for all real numbers, the domain of \( f(x) = \sqrt[3]{x} + 1 \) is all real numbers. Therefore, the domain is \( (-\infty, \infty) \).
03
- Range of the function
Because the cubic root function can produce any real number and we are adding 1 to it, the range is all real numbers as well. So, the range of \( f(x) = \sqrt[3]{x} + 1 \) is \( (-\infty, \infty) \).
04
- Critical points and behavior
To find critical points, find the derivative of \( f(x) \): \( f'(x) = \frac{d}{dx} (\sqrt[3]{x} + 1) = \frac{1}{3} x^{-2/3} \). The function is never zero, so there are no critical points. The function is always increasing as \( f'(x) > 0 \) for all \( x \).
05
- Graphing the function
Visualize the graph by plotting key points of \( f(x) = \sqrt[3]{x} + 1 \). Points such as (0,1), (1,2), (-1, 0) illustrate that the function consistently increases and passes through these values.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Domain and Range
Understanding the domain and range of a function is crucial. In this case, we have the function \( f(x) = \sqrt[3]{x} + 1 \). The domain of a function defines all possible input values (x-values) for which the function is defined. For cubic root functions, the cube root is defined for all real numbers. Therefore, the domain of \( f(x) \) is \( (-\infty, \infty) \).
The range of the function represents all possible output values (y-values). Since the cubic root function can produce any real number, adding 1 to this function will still produce any real number. Thus, the range of \( f(x) = \sqrt[3]{x} + 1 \) is also \( (-\infty, \infty) \).
Understanding the domain and range helps in visualizing and graphing the function effectively.
The range of the function represents all possible output values (y-values). Since the cubic root function can produce any real number, adding 1 to this function will still produce any real number. Thus, the range of \( f(x) = \sqrt[3]{x} + 1 \) is also \( (-\infty, \infty) \).
Understanding the domain and range helps in visualizing and graphing the function effectively.
Derivatives
Derivatives are essential for understanding the behavior of a function, such as finding critical points and determining whether the function is increasing or decreasing. To find the derivative of the function \( f(x) = \sqrt[3]{x} + 1 \), we use the power rule.
Recall that \( \sqrt[3]{x} \) can be represented as \( x^{1/3} \). To find the derivative of \( x^{1/3} \), we use the rule: \( \frac{d}{dx} [x^n] = nx^{n-1} \).
Applying this rule, we get:
\[ f'(x) = \frac{1}{3} x^{-2/3} \]
This indicates how the slope of the function \( f(x) \) changes as \( x \) changes.
Since \( f'(x) = \frac{1}{3} x^{-2/3} \) is positive for all real numbers \( x \), the function is always increasing. There are no critical points (points where \( f'(x) = 0 \)), further confirming that the function is steadily increasing.
Recall that \( \sqrt[3]{x} \) can be represented as \( x^{1/3} \). To find the derivative of \( x^{1/3} \), we use the rule: \( \frac{d}{dx} [x^n] = nx^{n-1} \).
Applying this rule, we get:
\[ f'(x) = \frac{1}{3} x^{-2/3} \]
This indicates how the slope of the function \( f(x) \) changes as \( x \) changes.
Since \( f'(x) = \frac{1}{3} x^{-2/3} \) is positive for all real numbers \( x \), the function is always increasing. There are no critical points (points where \( f'(x) = 0 \)), further confirming that the function is steadily increasing.
Graphing Functions
Graphing functions allows us to visualize their behavior. For the function \( f(x) = \sqrt[3]{x} + 1 \), start by plotting a few key points. Notable points include:
By plotting these points, you will see that the function consistently increases. The cubic root function itself has a characteristic shape, and shifting it upward by 1 unit retains this shape but moves it up.
This visual understanding, combined with our knowledge of the function's domain and range, allows us to effectively graph and interpret \( f(x) = \sqrt[3]{x} + 1 \).
- When \( x = 0 \), then \( f(0) = \sqrt[3]{0} + 1 = 1 \). So, the point \( (0,1) \) is on the graph.
- When \( x = 1 \), then \( f(1) = \sqrt[3]{1} + 1 = 2 \). So, the point \( (1,2) \) is also on the graph.
- When \( x = -1 \), then \( f(-1) = \sqrt[3]{-1} + 1 = 0 \). This makes \( (-1,0) \) another point on the graph.
By plotting these points, you will see that the function consistently increases. The cubic root function itself has a characteristic shape, and shifting it upward by 1 unit retains this shape but moves it up.
This visual understanding, combined with our knowledge of the function's domain and range, allows us to effectively graph and interpret \( f(x) = \sqrt[3]{x} + 1 \).